It is not clear from the question what has happened. Have you recently come out of a relationship? It is apparent that you have had an unpleasant experience recently and are feeling emotional pain and suffering. It is normal to feel disturbed after a breakup but to excessively feel sad and not able function well needs attention. You are feeling worthless, you may even feel powerless and helpless. You are very young and you need to share about this situation with someone you trust, you need to vent out the blocked emotions. Feelings, thoughts, situations are all temporal. Eventually you will feel better. Have positive outlook and seek professional help.